Send and receive signals in parallel

Community Support
1

Hi guys,

Could you help me pls, I’m trying to send signals in parallel:

var ws sync.WaitGroup
	ws.Add(chunks)
	for i := 0; i < chunks; i++ {
		go func(num int) {
                        // some action here
			time.Sleep(time.Duration(rand.Intn(10)) * time.Second)
			logger.Info("Extraction", "chunk", num)
			signal := MySignal{
				Message:  "Please merge chunk",
				ChunkNum: num,
			}
			wf := activity.GetInfo(ctx).WorkflowExecution
			err := cli.SignalWorkflow(ctx, wf.ID, wf.RunID, "chunkExtracted", signal)
			if err != nil {
				logger.Error("Error sending the Signal", err)
			}
			ws.Done()
		}(i)
	}
	ws.Wait()

but it looks like they still sent sequentially…probably I’m doing something wrong, I would appreciate for any help…

2

ok, I’ll reply to myself, in case someone is looking for the answer.
To receive signals in parallel you have to use Temporal goroutines, in my example it looks like this:

resChan := make(chan string, chunks)

	for i := 0; i < chunks; i++ {
		workflow.Go(ctx, func(gCtx workflow.Context) {
			signalChan := workflow.GetSignalChannel(gCtx, "chunkExtracted")
			selector := workflow.NewSelector(gCtx)
			selector.AddReceive(signalChan, func(channel workflow.ReceiveChannel, more bool) {
				var signal MySignal
				channel.ReceiveAsync(&signal)
				var result string
				err = workflow.ExecuteActivity(mergeCtx, "NextActivity", signal.ChunkNum).Get(gCtx, &result)
				if err != nil {
					return
				}
				resChan <- result
			})
			selector.Select(gCtx)
		})
	}

	workflow.Await(ctx, func() bool {
		return len(resChan) == chunks
	})